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Fix unwinding through x86-64 __bionic_clone.

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x86-64 needs these CFI directives to stop unwinding here.
I've also cleaned up the assembler a little, and made x86 and x86-64
a little more alike.

Bug: 15195760

(cherry picked from commit aeb3016f8132689d1b49d30056005b667e3d2d0e)

Change-Id: I511fe238b1ef1a1c16aef735f93bbee9accb0689
This commit is contained in:
Elliott Hughes 2014-06-05 12:28:14 -07:00
parent 430cf1a6c3
commit bd7a892c30
2 changed files with 17 additions and 9 deletions
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6
libc/arch-x86/bionic/__bionic_clone.S
View File

@ -25,8 +25,8 @@ ENTRY(__bionic_clone)
int $0x80 int $0x80
# Check result. # Check result.
cmpl $0, %eax testl %eax, %eax
je .L_bc_child jz .L_bc_child
jg .L_bc_parent jg .L_bc_parent
# An error occurred, so set errno and return -1. # An error occurred, so set errno and return -1.
@ -44,7 +44,7 @@ ENTRY(__bionic_clone)
hlt hlt
.L_bc_parent: .L_bc_parent:
# we're the parent; nothing to do. # We're the parent; nothing to do.
.L_bc_return: .L_bc_return:
popl %edi popl %edi
popl %esi popl %esi

20
libc/arch-x86_64/bionic/__bionic_clone.S
View File

@ -45,17 +45,23 @@ ENTRY(__bionic_clone)
# Make the system call. # Make the system call.
movl $__NR_clone, %eax movl $__NR_clone, %eax
syscall syscall
testl %eax, %eax
jns 1f # Check result.
testq %rax, %rax
jz .L_bc_child
jg .L_bc_parent
# An error occurred, set errno and return -1. # An error occurred, set errno and return -1.
negl %eax negl %eax
movl %eax, %edi movl %eax, %edi
call __set_errno call __set_errno
orl $-1, %eax orl $-1, %eax
jmp 2f ret
1:
jnz 2f .L_bc_child:
# We don't want anyone to unwind past this point.
.cfi_undefined %rip
.cfi_undefined %rbp
# We're in the child now, so call __bionic_clone_entry # We're in the child now, so call __bionic_clone_entry
# with the arguments from the child stack moved into # with the arguments from the child stack moved into
@ -64,7 +70,9 @@ ENTRY(__bionic_clone)
popq %rsi # arg popq %rsi # arg
call __bionic_clone_entry call __bionic_clone_entry
hlt hlt
2:
.L_bc_parent:
# We're the parent; nothing to do.
ret ret
END(__bionic_clone) END(__bionic_clone)
.hidden __bionic_clone .hidden __bionic_clone